SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6eb625caac042be70eff199e37651a2358aaf57d9714848856ec1e10da16f5ee' 
  AND token = 'lMiAsqmWZ5xA+hPgR3IPsdLe92ozyJhGofIv+ceqvDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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