SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f137d14b03f06c5305c8faa1487a6f4c09b7064358b1ed045fa9e82d46581dcd' 
  AND token = '8jqvkpZe0tS0iOce6qEFHZuwp/uFkqfa8N6BI0u6lQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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