SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '94cf0b4c1723cdd5cf6c6a170367d4ef246ed388a5faaa535c3297475556ef1d' 
  AND token = 'bZLgFJdqAXgYIAqHHIsyRx3o1w00r1KWLuSDQl8Py/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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