SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd91838cf793c155130522a339a929a926674f956815c3c0dba0c3e0e6b56d102' 
  AND token = 'JVqvPLE6H+I1Xr8lSSrnMnGXcfmoJ5ugrZDQMEfB5RE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

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