SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2f46c37c27c39dc0a2421fe68dd1ecc92c8dbcd9557ffaf575b4cf7cc6d23380' 
  AND token = '/Tw/1L88MJt1Pf2n6iAvsudoCEO/9NVRpQczaSRYApo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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