SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ff404fc6ab70440a9ed2b059ca75c3434a7be68e037c68363a10054960b70e7' 
  AND token = 'p9MSs/dLrcwoo3aqoPt1HnTQ2R5lt6xz1YEGq/xcAUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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