SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c56124d80ebda3449218a787ac619ccdf4f65c10588d9d0d01937b3a3cecdc1' 
  AND token = 'mY+cyIqRkmfcUdPE7FIpL7ALft6krBYkg8n4CPLRqKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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