SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8e977940d1d758ae73d19bc9c69d1b19a10728fad9a75b5b33ca617baa2cc45' 
  AND token = 'c3tdcZRbZRmxLBVgWlMCBADi6ho8s+1fl2z0sgKnV58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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