SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2eb8861407e460837476705a3396f82349c65e8c689168b983c8e41a58c25741' 
  AND token = 'VI2yZHPIHhKBGRUSaiRjAGfCvmWylLWpjH0FK1Fq/14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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