SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '54635700db3b107951cef8b17392978c4b31c81846a58ce21cdab6e175d82466' 
  AND token = 'w+y6i/v0IxusZGDesqAjrbwJ+tmOoUaacSPYUuKyCOo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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