SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7d45f890db3b5aaa776fdb8fea58870e38f075752bccee0ae8f4aa408b63a75' 
  AND token = 'ccvJ6IewHNeR+a2Km7WPbFyHPpwjrZ8nC/xvZvlVsPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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