SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42b4c8e9db9ebd53fb50451a589630351efea2c3ff9003806838dfba44af5fd3' 
  AND token = 'RnFP1qNB+VFoZeSn3k0YKxpn1nRxOcun7SIFR4l4gsM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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