SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b347d0598b75505b5bacbdad2ade36c73f8f9e4e126157098259edd8980f9ca9' 
  AND token = 'yHhGZSEXn7nGVDbl9zT/6Wyzi0kdl/lmklHBGRIixyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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