SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ab8c69907319d77c2c0b7d94d6e417930d9d87faf8b4322b9aac48b590beb2d' 
  AND token = '/WTfYDzX8mHwC4vycrkC7G/txFQxvPoxudMoGPYHzJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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