SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88afceebdabc17ffcc1499d13a4d93d7acd65673016f83811991671f9186a4b9' 
  AND token = 'Up/GZrTAgcxSH7tD7n8KmjOBwdP0i8u+rQt1NqTsMLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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