SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8de05ce78510620a3fd979b9ebf8ca6f9fddaee8774d54aa30402bf2a3cae560' 
  AND token = 'Osh+2DnzQpsdJ5q9xSlBj4NOk/DJZfpn0RmVtMF2zvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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