SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a17395a127ecca9907c950a3a15fbe416b36b376e43cd0dc10316951e85373da' 
  AND token = 'vFxZwu3bo8rGDxCbKHS1j4UB1RKqJC9Vj0lfPDugI38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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