SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'bea1274c7885e91f708db9c722269bfc22f9f069dd52fc5076f0694b5ef81171' 
  AND token = 'EKsK+yG7Hcs2kkp1EdyV6Pzwqzi6Ks3uuJxkqyGDw+c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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