SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89e1d46b1fbb3bdb81dbb80ad7fddc0e801c38ad32b6e685321b8ecb4fb20863' 
  AND token = 'f7yswHqBTuzsbrfT4k2D2GcW5ueY+2tJWAlXGfCL/DE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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