SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d39e42edde38ef7d9016c0618e48689f14366dba196f6643081716103481b6f' 
  AND token = 'bWMA+LMdo2sxJ9EmNAWTYeapBUXQBCUxsiSMtTiV/zk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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