SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b01527d04131443e23856a9ffac00948f3914ecd3d4f9b850eb90359619606d' 
  AND token = 'M1ulh+NCEzjJN5Uc1f/qMAzMSeWvsdG83hguJcqhHIs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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