SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f37e849aa0bb234c989513f0a217c9f8ee01715416370f4349ee66209787091' 
  AND token = '89E5OumMUh7qYhAHUwk+rJN9Vi46rpwbsQgqVBXK0Vs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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