SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0eb83d8de4c91a2cc1eb48a2fe899221ef7c4c8c52ad24982b71b534f9272cd4' 
  AND token = 'RtVjVUZWPO4L7eSNhjxStos4uWIWjElBWLSyfhHK6nc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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