SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b3b13865dd3dd36fda6946beafcb7cc18dd802e81868f28dbc0e61d0e9bf680' 
  AND token = '/LMB2B114jm1vh/PxPekr3+NGqN4XedRFZozKHJ5DIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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