SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98e71628dee32f675e7e3bb8bb2bc2bcffed653c8becc0bbe1f5d099c4a39c41' 
  AND token = 'dLqzztbdSfrO7AIiKK0hNv92C4o7AwPpCW5nSP6gO8o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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