SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55bd72a87394d17c3096afd6b96d6912fe2ea9ecff9d0a8cc4112196b1a578f3' 
  AND token = 'kHlHMD2w+jrgePYc5vd6xWkBp9/5fGbBXUOgWp8PnnY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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