SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '574540e53804d20d5064a097061330de23623aa04c3053d61b316ce27d903bd0' 
  AND token = 'hR6ePVLhhrMGYoAIdmUsjhWCyS72HRN/buTTNfyvT1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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