SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8507f0daa6f8880a4b0aa7e7891e44de08c9347edef709687f528cc07966c5b7' 
  AND token = 'jG3a/rLEHqEUBFvJMm0FHeEfZhl4hBGWMcgoWHh/NUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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