SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92ab763474742b8b8f9853bbf31927fed9d537fab835c5e92f6bbb5407e3ad91' 
  AND token = 'hRt2xHi+NwfykFFd+3jZ5tMYdoaW5vri09FLGZne5W0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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