SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '54fa82131146813d93560aa5e148a02fd1d04e4559c675d633926bc7d6542aa5' 
  AND token = 'BKCfKuSfKT6z/kzX2G6y+QBC49hXQkv/2yNDCL3qLJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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