SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ac55ffd4e4a819143335e6956fa5d4febf85acac152eddc82fcdb1684a64e97' 
  AND token = 'Owd4Q9BXMFfMzqhOG1fxLQXb6looUiVuGFsutNJcSBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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