SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1a2a27a815832e178228784c76f885a59c09dbfed0503bd8de1b2b18d64bd15' 
  AND token = 'nw1L2i7fAEwX8IGNzuZkoLnfRPavvpyO9DaPet5yuR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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