SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bc81953463d018b38ed3702ecea001a5e189cb8033cfd705eec2eeebdcad3a1' 
  AND token = 'zO3/gkkKUqD6mCpl50CQrsvBiOn6DFuXisGnx3euGnA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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