SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '750707c52c74314c5ea4305a3384be322bbd0c23008b5d2b72fad375b4a5a502' 
  AND token = 'mt8KhwdiK9l2gs2kKTfZrKJORm7ODKtNY4g+bmtWNSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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