SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d7c4a784f384daf7492a504dc1b029b43866105be1313f84b3076249704debd' 
  AND token = '4Pd+F6lO2NckjUwxtjpWbCTxEQUbsWJ3OHGw0hlOLyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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