SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4883670a4afcd5e385f715ad02a6a05926c3cc01483178e679083901996a9a30' 
  AND token = 'EKCqVRgha7pNYG10qLSwOJd471xTYNOJ61oN+dhFH/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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