SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d11e76742a1ad0e6c7708e982847f7cb9c383a83670a74effa19ea040219dcc' 
  AND token = 'mkyeM3pkWaxgcOTlyQkeIFRuIKJFwpMntr7S+O+zMvo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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