SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a2ee66d800a8230f71feddcefde995aa7bde633413f7c4f0fefa2b4f53130c4' 
  AND token = 'b8d0dqPKvujUTtdnRJM0SQw+yogWnh9MouTCV3UTQG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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