SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '889a4b970f247c0ad5de28604627814740f3b33989423f70a8e9cd173ccba488' 
  AND token = '0PX5sZJbYAlyAO2H0TVS7Q+mEFcv8hx6KU9Yz2o5CEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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