SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '498d6051fffd5e27207dfe50ad35be0e0efbaf4979c07b21e83590e407f81d39' 
  AND token = 'LkpXKbnSqgueZwedDL7/uKFTAcMtgMjjB00NKLpXRvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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