SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '748b8cc611727523f273776252c7c2a5518e6af08af7ed21513bf66960082d84' 
  AND token = 'rxMGVZXyhSwa9RQHa6UdROhl6+Yp7Bwg7TjfYDLpwgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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