SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c2ae1532fc7490376470571e2c37b8e2e1aff36df2d8cac187b663edb12d8d16' 
  AND token = 'nxU8Eo/rfaJFAb02xTo/CMw5xlOnv/snh0Ghzb/jrr0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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