SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '117aeb71e098016bc0a52cede188bb516de597e06fab2a7d0bb57bbc3f29363d' 
  AND token = 'beblkffxiRzfbfpQVXF6UUeJxjXd79xxZolefBx/Xtk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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