SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c6fc12f4173e1fd1f626f6f33aef585cd48154350f89123bb5727d812680406' 
  AND token = '6oHul5/hr7TbHjaz2RestRB36tMIQP+5o63s/+k3MPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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