SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88b08074d2231bc75870dbf78526ea811cb6c64ce48834114379123e2c0cf51f' 
  AND token = '2QocsiPXPSmSMnKf/LPpa2CqKmVLMEV6W2DS1g8W/YQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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