SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d016c47b306d373c808cafb19848c9e795ae252d5dffd514cb34438d39cd7a6' 
  AND token = 'hfZCMPhfDvY600/Su2OboC83YPux8dDFS8jnLx4nb+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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