SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea3027820f3a7bca635b26cfc4a291350c43a4958f565c73972277d643b71775' 
  AND token = 'SZ/TOQVhWDQSgPJIN+vhr1B4TyT2I9bUnY08d8nU/+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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