SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d5554eda31734d92a08ea633c741f9a2ad183fae96f8af35770cf587acaa0eb' 
  AND token = 'MNn6UKvlmp/11fGMabvkQ2zRYEmzrGVx1Th5h8I1CwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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