SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0aed3a8201a919d1ec859ee354801b16a5205dc55373a485614526c81e60d419' 
  AND token = '2Lmpjtiz6IDRcw5Uk/Va9ZehvWVuIj+s3myzJCeRIOM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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