SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c931548e882466bd5ee279932f8ce9090be82a42386e58c6c09bcfc428f5d87f' 
  AND token = 'czVpUKYUl/ezL+JGj2v7YlPhPHjr7342ZzU6EiMLnEU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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