SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f155e0978d5866b4b14c14774e1d9823263a1c9b3e8c9f22350014b40e4dbbb7' 
  AND token = 'VYT4wbA0jhZh3EWsAQlOkSylyFaZ+Qoa1MvGTQy3EPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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