SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8793eba08be11d87fe8b3af77a567836219203adca22a763f5c869f10a97da05' 
  AND token = 'P2eztL3Ambn9wke4CFsmHMZ/1GfIDoiND1Fq9waA7uI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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