SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f68594c164db1d795b9c57bb1da748768e779810b846001bfaac08786f07942e' 
  AND token = 'pxsG6BKu9Y68EXYcsw7IuaEVWy9p3ZHW+Am798p9Chs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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