SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '910d35bf33492d9b87c5c12b058a76ac346ab117bee852c5d47869e1db629736' 
  AND token = 'UeizvwrFkOimymgYjLTorBJOYDLFAkxHr0ChA71NOZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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