SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5539989a62c61dcd357595b7741423b80fd43b07ecd16120b04ad86d4f884313' 
  AND token = 'mga+Hz6s+WbYAXaGvl8zqStMgXmsniCEgjZPILxdtA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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