SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '115ea8604c5636e13675a8e6aee8dc3194dc8aafde2eb71acbea3c31356d2f3a' 
  AND token = 'YOm0vNzQGIqaB2cRwMs+P6nuyfLKcAFlrQgZwNd0hzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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