SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '378f140d148f028b8826285d875f05d78a0ca1cd262513df80ac20352f4287f2' 
  AND token = 'Fo7GwLH9/7iUDaD5+R1C3SjH3twBuhc7iYwUhK5g5V4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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