SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a98a6be69636f33795fecbda8062f05b84cf1266599e10f0a3b7d194380c533a' 
  AND token = 's+VebKapd3oh9MC7D28vEJPkYTfkTuXSjHOaBgRh3sY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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