SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f743ca8830f9e843fa403315c3ff379838f4721f9b61b5142a45604689b957d1' 
  AND token = 'y9Gl2oH65hPGYmdkcpyBH43dPHGWP3uOQuumBap0D18=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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