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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef4d3a60292c6a8fd2fd8cae4f5a0ef3e435ec98b98b3402bf76bbfe0ff6a227' 
  AND token = 'HUk3gx8dRvzYK+f9UiPIF7Edde/sHZbgHHVx6Urbqk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}