SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11938d2bd7130f18f6a296148ec542be717d7b635b383d0797fd196266e9c894' 
  AND token = 'lfCcJR3npfgA9hw5StURr4mISqLeRELu07E3UuQQqkc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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