SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e38b4b1df79390c655c5b0cbf3ef9371970843886fca0ed0cb10f681f3bebc84' 
  AND token = 'DYFnwg6Ahdue5zPiAnY+NVgW1nuphpHXzQH1TAqXr24=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}