SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'dbcf4deb8dc9d0fb70f96f1bf57cc4c72528fa0a2266a2058e6444e20e49e838' 
  AND token = 'rtRfSO9/KHblhUshK/RoYJtWXFL5BmTGnzIxEcbNqf8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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