SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9ba46c3f23f3463e8d07232974635dd9f6cd5cba8069241ddd10f6f9b5d2017' 
  AND token = 'gFTET6WNznJAGSWlJFhNsjg1/kkK4v7CnwQ6t7FC9kU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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