SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '415e9a34adcc4d200f96aba4a673538487d3e8ef624bec5dac01da3935e6dcf1' 
  AND token = '/Jc712PJ82FTZYuSxnSynusHcSw8GToAFeeAUyizDs8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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