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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e57fb7de4a4b52976e11dcd6672942cbfecf993bc93b6a0c9f8f1fba2254f8dd' 
  AND token = 'k7IL8CPgwZ264Rk8dCOzM5y3dFZod8IqMD9rbpX8+f8=' 
  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"
    }
  }
}