SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd167668f6daedf863e514047039114dbd68bfd8dcf8dd92d831a16b20a8c809' 
  AND token = 'hE0hmRQSYwOe06QeZ4I31A2vAqsCHi4jMCkduoarPEg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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