SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '673d1cda4021af9d59d923f8cb2445216a68b70df05324a363f552a163214af8' 
  AND token = 'HmVMy1GmFbS+dP8vr3aki7eQ8DsfzOV64tD/xHPnEVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}