SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6050e3647c1d188cfa5510ae390e7a01f1293651a6194145ce8699706504778' 
  AND token = '9m+s9pFXzL2/9VlaBgeh5nIK2yw4vHziqZwER2KNrx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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