SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '780f2a34c351089018fafe6799c548b48f370f8a4a51c452b2e6454e2517092f' 
  AND token = '9LuGIRbTfIhD5ewDGrdtKpLhZiTuXyOYS+G2pcTu5/8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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