SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f37269184312425c68227ce3dae618cda9b54698617808ab268ff419aa355534' 
  AND token = 'L4xmuMAjSxw0eMoPS8GiChNLrMFZNmZD/q2dMFz+r7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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