SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '496bf18d07062f9f78a83785464fbfd1030b6b05ef9d7c7dd48b8d9550aaa8e7' 
  AND token = 'ev2WtkCpGGHzJ3LRgR5g6j8qkz66Vw+sWPvHAhTVMy8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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