SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7fa53efc7c6521dd61dfe840e012bbf0c3f2256269c36b459d936f8db712d41' 
  AND token = 'NVUyjqdoouv2ZDy60nIgAbBcTtwLKVLRxnjmQJJLSdk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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