SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b95390bc2d1f97b9704ec90752c6541187d98754ed28b2f8aa568627fb69bf90' 
  AND token = '0BhIn4sJUKO69oYW+zmYm0JiCiyjmV6ce0ktMS8twGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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