SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '837a308367663aeb0318bdf6544a244acb0c59f3cbbc5b2ecdd244acea9806d8' 
  AND token = 'zMU8DrFOg9Q/a86o+Ueq5SWqgJDS6rqXMPwVVlOAP9s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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