SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '106017e1c3979d85c2a0473043545fd67a298fa18a291b41c96b6a51c095249c' 
  AND token = 'NVCx9v5R/GTf7wu8AcTgN32OFHZdOvpJSLhbBKN+4wo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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