SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12cd699d821b19337dbf8bfc039bf7604317b0ce17555672a890e7c563e152db' 
  AND token = '3fHis/KlGcafSlhdD/rA0fhbSJXzhZLSGHP3UqANIjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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