SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c196c20ad75e1d2d1aee4f310bf1e2bbf308d803ed6118bcfa24ca8a8a51d96' 
  AND token = 'VSWoXZCK7JGH9VjSQhzNjlSFlOsGIV+UELuWjgzoavY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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