SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '68b34311c8100af88f2f795c3c9653cf23aa5fbdfae132aa1fa3a746bc66de3b' 
  AND token = '//Y5GryHW4JTYmVeAPV6/kV2vi0FIW3PIakQiHcvaEY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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