SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '665fcf663f3d09a5fc4b84f34d887953106a2fa255ed7af95af19e2255ac2bab' 
  AND token = 'xouBUAZfrKH/iiuFDksRFpRKLbXqM47ETGRmO8413gU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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