SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd801bb3f81f2470a4b2400f0616c4f50ab8013fe609add12b83001cc54788294' 
  AND token = '1vqCo6ClCoIzjoNZt1NrZfE6unLKd5IBjPo3CrKE+nI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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