SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5666e3ea1180244b4a002a69f8a12d1d3d22327f27fda551dd35d984949c1921' 
  AND token = 'gR8q2amyV5zI7PY/Q8UA17WR+MYidUy5bp5JjB/H8JA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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