SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee2ac7d2b147e17150066cad8910c977a1a59045243ae1da2b064adfd1b13557' 
  AND token = 'U0x0aBoHKJ961jWuXFtHmgoNImvIYg55ekQtoPd5wX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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