SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ed65818714352e7e2cc2c02cb9f4c8442f57721e740c875b2b051e40532f2aa' 
  AND token = 'FAEbXdVJ4pCiHFC5FJIXqzMNcjiu/bGsKxeHTkryqMI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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