SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e146b39eecdcdac53472e16b43bbaa1627f60487fec2d126f7111949ffd02381' 
  AND token = 'aiYi+gqm1/zF0mKFGifTQ6k2uU9+KwAxsBsw7pNpSLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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