SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3493f7434802baf886354841070ac1ec2185e5c636be14816f8850e7160dbffa' 
  AND token = 'mBTM2rtiq9BhRkiNsrg3KHnfHUeb323ytTzQKgn1a+c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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