SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fab1abc2741ecb0441137023818c8789855686295ee15792ac2963f250d38df6' 
  AND token = '9QnwMl56iEDkQunKEGQg27wZ5iP06zHbOWhwaNf66MY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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